Technical Field
The present invention relates to integrated circuit analysis and more particularly to a system and method for localization and resolvability of an integrated circuit using a set of stimuli to provide varying images for analyzing of the circuit.
Description of the Related Art
Analytical tools are commonly used for characterizing, testing, and debugging VLSI circuits. Some tools and techniques, such as emission tools based on off-state leakage currents and laser based stimulation tools, focus mostly on improving manufacturing process steps such as reducing leakage and variability, or improving performance and yield. Other tools and techniques, such as Time-Resolved Emission (TRE), focus mostly on probing time dependent signals from specific nodes and transistors of very large scale integration (VLSI) circuits to understand behavior and performance. In another type of application, some faulty behavior of the chip may be investigated to understand the cause and possibly guide process engineers or circuit designers to fix a problem in new releases of hardware.
The continuous trend of modern complementary metal oxide semiconductor (CMOS) VLSI circuits towards miniaturization makes the precise localization and interpretation of the measured results more and more challenging. In particular, some features of interest have become smaller than the theoretical diffraction limit of the optics available to the modern microscope and analytical tools. These needs have sparked many developments in many areas such as optics, image processing, detector technology, etc. In particular, Solid Immersion Lens (SIL) has replaced the conventional air gap microscopy lens permitting a significant increase in the numerical aperture of collection optics, thus increasing both the lateral spatial resolution and the collection efficiency. Developments continue since such techniques are commonly used by most analytical methods in this area.
Additionally, image post-processing techniques have been proposed and are under evaluation to improve signal separation for tools that provide 2D images of samples such as static emission tools, laser stimulation tools, and 2D TRE tools. Detector improvements are also under way to increase the sensitivity to small signals as well as increase the number of pixels and reduce their size. For certain techniques, such as 2D TRE, the availability of three dimensions (x,y,t) permits additional room for separating signals since events taking place in close spatial position but at different instants in time may still be separated.
Many types of methodology improvements are also being proposed, mostly specific to particular analytical techniques. For example, two photon absorption may improve lateral spatial resolution of laser stimulation techniques. Additionally, near field microscopy, with all the complications and limitations associated to it, may lead to increased spatial resolution in static emission measurements for certain localized areas of interest.